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Java example source code file (methodHandles.cpp)

This example Java source code file (methodHandles.cpp) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

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Java - Java tags/keywords

fn_ptr, handle, is_method, jvm_end, jvm_entry, klasshandle, mem, null, obj, reference_kind_shift, symbol, thread

The methodHandles.cpp Java example source code

/*
 * Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#include "precompiled.hpp"
#include "classfile/symbolTable.hpp"
#include "compiler/compileBroker.hpp"
#include "interpreter/interpreter.hpp"
#include "interpreter/oopMapCache.hpp"
#include "memory/allocation.inline.hpp"
#include "memory/oopFactory.hpp"
#include "prims/jvmtiRedefineClassesTrace.hpp"
#include "prims/methodHandles.hpp"
#include "runtime/compilationPolicy.hpp"
#include "runtime/javaCalls.hpp"
#include "runtime/reflection.hpp"
#include "runtime/signature.hpp"
#include "runtime/stubRoutines.hpp"


/*
 * JSR 292 reference implementation: method handles
 * The JDK 7 reference implementation represented method handle
 * combinations as chains.  Each link in the chain had a "vmentry"
 * field which pointed at a bit of assembly code which performed
 * one transformation before dispatching to the next link in the chain.
 *
 * The current reference implementation pushes almost all code generation
 * responsibility to (trusted) Java code.  A method handle contains a
 * pointer to its "LambdaForm", which embodies all details of the method
 * handle's behavior.  The LambdaForm is a normal Java object, managed
 * by a runtime coded in Java.
 */

bool MethodHandles::_enabled = false; // set true after successful native linkage
MethodHandlesAdapterBlob* MethodHandles::_adapter_code = NULL;

//------------------------------------------------------------------------------
// MethodHandles::generate_adapters
//
void MethodHandles::generate_adapters() {
  if (!EnableInvokeDynamic || SystemDictionary::MethodHandle_klass() == NULL)  return;

  assert(_adapter_code == NULL, "generate only once");

  ResourceMark rm;
  TraceTime timer("MethodHandles adapters generation", TraceStartupTime);
  _adapter_code = MethodHandlesAdapterBlob::create(adapter_code_size);
  if (_adapter_code == NULL)
    vm_exit_out_of_memory(adapter_code_size, OOM_MALLOC_ERROR,
                          "CodeCache: no room for MethodHandles adapters");
  {
    CodeBuffer code(_adapter_code);
    MethodHandlesAdapterGenerator g(&code);
    g.generate();
    code.log_section_sizes("MethodHandlesAdapterBlob");
  }
}

//------------------------------------------------------------------------------
// MethodHandlesAdapterGenerator::generate
//
void MethodHandlesAdapterGenerator::generate() {
  // Generate generic method handle adapters.
  // Generate interpreter entries
  for (Interpreter::MethodKind mk = Interpreter::method_handle_invoke_FIRST;
       mk <= Interpreter::method_handle_invoke_LAST;
       mk = Interpreter::MethodKind(1 + (int)mk)) {
    vmIntrinsics::ID iid = Interpreter::method_handle_intrinsic(mk);
    StubCodeMark mark(this, "MethodHandle::interpreter_entry", vmIntrinsics::name_at(iid));
    address entry = MethodHandles::generate_method_handle_interpreter_entry(_masm, iid);
    if (entry != NULL) {
      Interpreter::set_entry_for_kind(mk, entry);
    }
    // If the entry is not set, it will throw AbstractMethodError.
  }
}

void MethodHandles::set_enabled(bool z) {
  if (_enabled != z) {
    guarantee(z && EnableInvokeDynamic, "can only enable once, and only if -XX:+EnableInvokeDynamic");
    _enabled = z;
  }
}

// MemberName support

// import java_lang_invoke_MemberName.*
enum {
  IS_METHOD            = java_lang_invoke_MemberName::MN_IS_METHOD,
  IS_CONSTRUCTOR       = java_lang_invoke_MemberName::MN_IS_CONSTRUCTOR,
  IS_FIELD             = java_lang_invoke_MemberName::MN_IS_FIELD,
  IS_TYPE              = java_lang_invoke_MemberName::MN_IS_TYPE,
  CALLER_SENSITIVE     = java_lang_invoke_MemberName::MN_CALLER_SENSITIVE,
  REFERENCE_KIND_SHIFT = java_lang_invoke_MemberName::MN_REFERENCE_KIND_SHIFT,
  REFERENCE_KIND_MASK  = java_lang_invoke_MemberName::MN_REFERENCE_KIND_MASK,
  SEARCH_SUPERCLASSES  = java_lang_invoke_MemberName::MN_SEARCH_SUPERCLASSES,
  SEARCH_INTERFACES    = java_lang_invoke_MemberName::MN_SEARCH_INTERFACES,
  ALL_KINDS      = IS_METHOD | IS_CONSTRUCTOR | IS_FIELD | IS_TYPE
};

Handle MethodHandles::new_MemberName(TRAPS) {
  Handle empty;
  instanceKlassHandle k(THREAD, SystemDictionary::MemberName_klass());
  if (!k->is_initialized())  k->initialize(CHECK_(empty));
  return Handle(THREAD, k->allocate_instance(THREAD));
}

oop MethodHandles::init_MemberName(Handle mname, Handle target) {
  // This method is used from java.lang.invoke.MemberName constructors.
  // It fills in the new MemberName from a java.lang.reflect.Member.
  Thread* thread = Thread::current();
  oop target_oop = target();
  Klass* target_klass = target_oop->klass();
  if (target_klass == SystemDictionary::reflect_Field_klass()) {
    oop clazz = java_lang_reflect_Field::clazz(target_oop); // fd.field_holder()
    int slot  = java_lang_reflect_Field::slot(target_oop);  // fd.index()
    KlassHandle k(thread, java_lang_Class::as_Klass(clazz));
    if (!k.is_null() && k->oop_is_instance()) {
      fieldDescriptor fd(InstanceKlass::cast(k()), slot);
      oop mname2 = init_field_MemberName(mname, fd);
      if (mname2 != NULL) {
        // Since we have the reified name and type handy, add them to the result.
        if (java_lang_invoke_MemberName::name(mname2) == NULL)
          java_lang_invoke_MemberName::set_name(mname2, java_lang_reflect_Field::name(target_oop));
        if (java_lang_invoke_MemberName::type(mname2) == NULL)
          java_lang_invoke_MemberName::set_type(mname2, java_lang_reflect_Field::type(target_oop));
      }
      return mname2;
    }
  } else if (target_klass == SystemDictionary::reflect_Method_klass()) {
    oop clazz  = java_lang_reflect_Method::clazz(target_oop);
    int slot   = java_lang_reflect_Method::slot(target_oop);
    KlassHandle k(thread, java_lang_Class::as_Klass(clazz));
    if (!k.is_null() && k->oop_is_instance()) {
      Method* m = InstanceKlass::cast(k())->method_with_idnum(slot);
      if (m == NULL || is_signature_polymorphic(m->intrinsic_id()))
        return NULL;            // do not resolve unless there is a concrete signature
      CallInfo info(m, k());
      return init_method_MemberName(mname, info);
    }
  } else if (target_klass == SystemDictionary::reflect_Constructor_klass()) {
    oop clazz  = java_lang_reflect_Constructor::clazz(target_oop);
    int slot   = java_lang_reflect_Constructor::slot(target_oop);
    KlassHandle k(thread, java_lang_Class::as_Klass(clazz));
    if (!k.is_null() && k->oop_is_instance()) {
      Method* m = InstanceKlass::cast(k())->method_with_idnum(slot);
      if (m == NULL)  return NULL;
      CallInfo info(m, k());
      return init_method_MemberName(mname, info);
    }
  }
  return NULL;
}

oop MethodHandles::init_method_MemberName(Handle mname, CallInfo& info) {
  assert(info.resolved_appendix().is_null(), "only normal methods here");
  methodHandle m = info.resolved_method();
  KlassHandle m_klass = m->method_holder();
  int flags = (jushort)( m->access_flags().as_short() & JVM_RECOGNIZED_METHOD_MODIFIERS );
  int vmindex = Method::invalid_vtable_index;

  switch (info.call_kind()) {
  case CallInfo::itable_call:
    vmindex = info.itable_index();
    // More importantly, the itable index only works with the method holder.
    assert(m_klass->verify_itable_index(vmindex), "");
    flags |= IS_METHOD | (JVM_REF_invokeInterface << REFERENCE_KIND_SHIFT);
    if (TraceInvokeDynamic) {
      ResourceMark rm;
      tty->print_cr("memberName: invokeinterface method_holder::method: %s, itableindex: %d, access_flags:",
            Method::name_and_sig_as_C_string(m->method_holder(), m->name(), m->signature()),
            vmindex);
       m->access_flags().print_on(tty);
       if (!m->is_abstract()) {
         tty->print("default");
       }
       tty->cr();
    }
    break;

  case CallInfo::vtable_call:
    vmindex = info.vtable_index();
    flags |= IS_METHOD | (JVM_REF_invokeVirtual << REFERENCE_KIND_SHIFT);
    assert(info.resolved_klass()->is_subtype_of(m_klass()), "virtual call must be type-safe");
    if (m_klass->is_interface()) {
      // This is a vtable call to an interface method (abstract "miranda method" or default method).
      // The vtable index is meaningless without a class (not interface) receiver type, so get one.
      // (LinkResolver should help us figure this out.)
      KlassHandle m_klass_non_interface = info.resolved_klass();
      if (m_klass_non_interface->is_interface()) {
        m_klass_non_interface = SystemDictionary::Object_klass();
#ifdef ASSERT
        { ResourceMark rm;
          Method* m2 = m_klass_non_interface->vtable()->method_at(vmindex);
          assert(m->name() == m2->name() && m->signature() == m2->signature(),
                 err_msg("at %d, %s != %s", vmindex,
                         m->name_and_sig_as_C_string(), m2->name_and_sig_as_C_string()));
        }
#endif //ASSERT
      }
      if (!m->is_public()) {
        assert(m->is_public(), "virtual call must be to public interface method");
        return NULL;  // elicit an error later in product build
      }
      assert(info.resolved_klass()->is_subtype_of(m_klass_non_interface()), "virtual call must be type-safe");
      m_klass = m_klass_non_interface;
    }
    if (TraceInvokeDynamic) {
      ResourceMark rm;
      tty->print_cr("memberName: invokevirtual method_holder::method: %s, receiver: %s, vtableindex: %d, access_flags:",
            Method::name_and_sig_as_C_string(m->method_holder(), m->name(), m->signature()),
            m_klass->internal_name(), vmindex);
       m->access_flags().print_on(tty);
       if (m->is_default_method()) {
         tty->print("default");
       }
       tty->cr();
    }
    break;

  case CallInfo::direct_call:
    vmindex = Method::nonvirtual_vtable_index;
    if (m->is_static()) {
      flags |= IS_METHOD      | (JVM_REF_invokeStatic  << REFERENCE_KIND_SHIFT);
    } else if (m->is_initializer()) {
      flags |= IS_CONSTRUCTOR | (JVM_REF_invokeSpecial << REFERENCE_KIND_SHIFT);
    } else {
      flags |= IS_METHOD      | (JVM_REF_invokeSpecial << REFERENCE_KIND_SHIFT);
    }
    break;

  default:  assert(false, "bad CallInfo");  return NULL;
  }

  // @CallerSensitive annotation detected
  if (m->caller_sensitive()) {
    flags |= CALLER_SENSITIVE;
  }

  oop mname_oop = mname();
  java_lang_invoke_MemberName::set_flags(   mname_oop, flags);
  java_lang_invoke_MemberName::set_vmtarget(mname_oop, m());
  java_lang_invoke_MemberName::set_vmindex( mname_oop, vmindex);   // vtable/itable index
  java_lang_invoke_MemberName::set_clazz(   mname_oop, m_klass->java_mirror());
  // Note:  name and type can be lazily computed by resolve_MemberName,
  // if Java code needs them as resolved String and MethodType objects.
  // The clazz must be eagerly stored, because it provides a GC
  // root to help keep alive the Method*.
  // If relevant, the vtable or itable value is stored as vmindex.
  // This is done eagerly, since it is readily available without
  // constructing any new objects.
  // TO DO: maybe intern mname_oop
  m->method_holder()->add_member_name(m->method_idnum(), mname);

  return mname();
}

oop MethodHandles::init_field_MemberName(Handle mname, fieldDescriptor& fd, bool is_setter) {
  int flags = (jushort)( fd.access_flags().as_short() & JVM_RECOGNIZED_FIELD_MODIFIERS );
  flags |= IS_FIELD | ((fd.is_static() ? JVM_REF_getStatic : JVM_REF_getField) << REFERENCE_KIND_SHIFT);
  if (is_setter)  flags += ((JVM_REF_putField - JVM_REF_getField) << REFERENCE_KIND_SHIFT);
  Metadata* vmtarget = fd.field_holder();
  int vmindex        = fd.offset();  // determines the field uniquely when combined with static bit
  oop mname_oop = mname();
  java_lang_invoke_MemberName::set_flags(mname_oop,    flags);
  java_lang_invoke_MemberName::set_vmtarget(mname_oop, vmtarget);
  java_lang_invoke_MemberName::set_vmindex(mname_oop,  vmindex);
  java_lang_invoke_MemberName::set_clazz(mname_oop,    fd.field_holder()->java_mirror());
  oop type = field_signature_type_or_null(fd.signature());
  oop name = field_name_or_null(fd.name());
  if (name != NULL)
    java_lang_invoke_MemberName::set_name(mname_oop,   name);
  if (type != NULL)
    java_lang_invoke_MemberName::set_type(mname_oop,   type);
  // Note:  name and type can be lazily computed by resolve_MemberName,
  // if Java code needs them as resolved String and Class objects.
  // Note that the incoming type oop might be pre-resolved (non-null).
  // The base clazz and field offset (vmindex) must be eagerly stored,
  // because they unambiguously identify the field.
  // Although the fieldDescriptor::_index would also identify the field,
  // we do not use it, because it is harder to decode.
  // TO DO: maybe intern mname_oop
  return mname();
}

// JVM 2.9 Special Methods:
// A method is signature polymorphic if and only if all of the following conditions hold :
// * It is declared in the java.lang.invoke.MethodHandle class.
// * It has a single formal parameter of type Object[].
// * It has a return type of Object.
// * It has the ACC_VARARGS and ACC_NATIVE flags set.
bool MethodHandles::is_method_handle_invoke_name(Klass* klass, Symbol* name) {
  if (klass == NULL)
    return false;
  // The following test will fail spuriously during bootstrap of MethodHandle itself:
  //    if (klass != SystemDictionary::MethodHandle_klass())
  // Test the name instead:
  if (klass->name() != vmSymbols::java_lang_invoke_MethodHandle())
    return false;
  Symbol* poly_sig = vmSymbols::object_array_object_signature();
  Method* m = InstanceKlass::cast(klass)->find_method(name, poly_sig);
  if (m == NULL)  return false;
  int required = JVM_ACC_NATIVE | JVM_ACC_VARARGS;
  int flags = m->access_flags().as_int();
  return (flags & required) == required;
}


Symbol* MethodHandles::signature_polymorphic_intrinsic_name(vmIntrinsics::ID iid) {
  assert(is_signature_polymorphic_intrinsic(iid), err_msg("iid=%d", iid));
  switch (iid) {
  case vmIntrinsics::_invokeBasic:      return vmSymbols::invokeBasic_name();
  case vmIntrinsics::_linkToVirtual:    return vmSymbols::linkToVirtual_name();
  case vmIntrinsics::_linkToStatic:     return vmSymbols::linkToStatic_name();
  case vmIntrinsics::_linkToSpecial:    return vmSymbols::linkToSpecial_name();
  case vmIntrinsics::_linkToInterface:  return vmSymbols::linkToInterface_name();
  }
  assert(false, "");
  return 0;
}

int MethodHandles::signature_polymorphic_intrinsic_ref_kind(vmIntrinsics::ID iid) {
  switch (iid) {
  case vmIntrinsics::_invokeBasic:      return 0;
  case vmIntrinsics::_linkToVirtual:    return JVM_REF_invokeVirtual;
  case vmIntrinsics::_linkToStatic:     return JVM_REF_invokeStatic;
  case vmIntrinsics::_linkToSpecial:    return JVM_REF_invokeSpecial;
  case vmIntrinsics::_linkToInterface:  return JVM_REF_invokeInterface;
  }
  assert(false, err_msg("iid=%d", iid));
  return 0;
}

vmIntrinsics::ID MethodHandles::signature_polymorphic_name_id(Symbol* name) {
  vmSymbols::SID name_id = vmSymbols::find_sid(name);
  switch (name_id) {
  // The ID _invokeGeneric stands for all non-static signature-polymorphic methods, except built-ins.
  case vmSymbols::VM_SYMBOL_ENUM_NAME(invoke_name):           return vmIntrinsics::_invokeGeneric;
  // The only built-in non-static signature-polymorphic method is MethodHandle.invokeBasic:
  case vmSymbols::VM_SYMBOL_ENUM_NAME(invokeBasic_name):      return vmIntrinsics::_invokeBasic;

  // There is one static signature-polymorphic method for each JVM invocation mode.
  case vmSymbols::VM_SYMBOL_ENUM_NAME(linkToVirtual_name):    return vmIntrinsics::_linkToVirtual;
  case vmSymbols::VM_SYMBOL_ENUM_NAME(linkToStatic_name):     return vmIntrinsics::_linkToStatic;
  case vmSymbols::VM_SYMBOL_ENUM_NAME(linkToSpecial_name):    return vmIntrinsics::_linkToSpecial;
  case vmSymbols::VM_SYMBOL_ENUM_NAME(linkToInterface_name):  return vmIntrinsics::_linkToInterface;
  }

  // Cover the case of invokeExact and any future variants of invokeFoo.
  Klass* mh_klass = SystemDictionary::well_known_klass(
                              SystemDictionary::WK_KLASS_ENUM_NAME(MethodHandle_klass) );
  if (mh_klass != NULL && is_method_handle_invoke_name(mh_klass, name))
    return vmIntrinsics::_invokeGeneric;

  // Note: The pseudo-intrinsic _compiledLambdaForm is never linked against.
  // Instead it is used to mark lambda forms bound to invokehandle or invokedynamic.
  return vmIntrinsics::_none;
}

vmIntrinsics::ID MethodHandles::signature_polymorphic_name_id(Klass* klass, Symbol* name) {
  if (klass != NULL &&
      klass->name() == vmSymbols::java_lang_invoke_MethodHandle()) {
    vmIntrinsics::ID iid = signature_polymorphic_name_id(name);
    if (iid != vmIntrinsics::_none)
      return iid;
    if (is_method_handle_invoke_name(klass, name))
      return vmIntrinsics::_invokeGeneric;
  }
  return vmIntrinsics::_none;
}


// convert the external string or reflective type to an internal signature
Symbol* MethodHandles::lookup_signature(oop type_str, bool intern_if_not_found, TRAPS) {
  if (java_lang_invoke_MethodType::is_instance(type_str)) {
    return java_lang_invoke_MethodType::as_signature(type_str, intern_if_not_found, CHECK_NULL);
  } else if (java_lang_Class::is_instance(type_str)) {
    return java_lang_Class::as_signature(type_str, false, CHECK_NULL);
  } else if (java_lang_String::is_instance(type_str)) {
    if (intern_if_not_found) {
      return java_lang_String::as_symbol(type_str, CHECK_NULL);
    } else {
      return java_lang_String::as_symbol_or_null(type_str);
    }
  } else {
    THROW_MSG_(vmSymbols::java_lang_InternalError(), "unrecognized type", NULL);
  }
}

static const char OBJ_SIG[] = "Ljava/lang/Object;";
enum { OBJ_SIG_LEN = 18 };

bool MethodHandles::is_basic_type_signature(Symbol* sig) {
  assert(vmSymbols::object_signature()->utf8_length() == (int)OBJ_SIG_LEN, "");
  assert(vmSymbols::object_signature()->equals(OBJ_SIG), "");
  const int len = sig->utf8_length();
  for (int i = 0; i < len; i++) {
    switch (sig->byte_at(i)) {
    case 'L':
      // only java/lang/Object is valid here
      if (sig->index_of_at(i, OBJ_SIG, OBJ_SIG_LEN) != i)
        return false;
      i += OBJ_SIG_LEN-1;  //-1 because of i++ in loop
      continue;
    case '(': case ')': case 'V':
    case 'I': case 'J': case 'F': case 'D':
      continue;
    //case '[':
    //case 'Z': case 'B': case 'C': case 'S':
    default:
      return false;
    }
  }
  return true;
}

Symbol* MethodHandles::lookup_basic_type_signature(Symbol* sig, bool keep_last_arg, TRAPS) {
  Symbol* bsig = NULL;
  if (sig == NULL) {
    return sig;
  } else if (is_basic_type_signature(sig)) {
    sig->increment_refcount();
    return sig;  // that was easy
  } else if (sig->byte_at(0) != '(') {
    BasicType bt = char2type(sig->byte_at(0));
    if (is_subword_type(bt)) {
      bsig = vmSymbols::int_signature();
    } else {
      assert(bt == T_OBJECT || bt == T_ARRAY, "is_basic_type_signature was false");
      bsig = vmSymbols::object_signature();
    }
  } else {
    ResourceMark rm;
    stringStream buffer(128);
    buffer.put('(');
    int arg_pos = 0, keep_arg_pos = -1;
    if (keep_last_arg)
      keep_arg_pos = ArgumentCount(sig).size() - 1;
    for (SignatureStream ss(sig); !ss.is_done(); ss.next()) {
      BasicType bt = ss.type();
      size_t this_arg_pos = buffer.size();
      if (ss.at_return_type()) {
        buffer.put(')');
      }
      if (arg_pos == keep_arg_pos) {
        buffer.write((char*) ss.raw_bytes(),
                     (int)   ss.raw_length());
      } else if (bt == T_OBJECT || bt == T_ARRAY) {
        buffer.write(OBJ_SIG, OBJ_SIG_LEN);
      } else {
        if (is_subword_type(bt))
          bt = T_INT;
        buffer.put(type2char(bt));
      }
      arg_pos++;
    }
    const char* sigstr =       buffer.base();
    int         siglen = (int) buffer.size();
    bsig = SymbolTable::new_symbol(sigstr, siglen, THREAD);
  }
  assert(is_basic_type_signature(bsig) ||
         // detune assert in case the injected argument is not a basic type:
         keep_last_arg, "");
  return bsig;
}

void MethodHandles::print_as_basic_type_signature_on(outputStream* st,
                                                     Symbol* sig,
                                                     bool keep_arrays,
                                                     bool keep_basic_names) {
  st = st ? st : tty;
  int len  = sig->utf8_length();
  int array = 0;
  bool prev_type = false;
  for (int i = 0; i < len; i++) {
    char ch = sig->byte_at(i);
    switch (ch) {
    case '(': case ')':
      prev_type = false;
      st->put(ch);
      continue;
    case '[':
      if (!keep_basic_names && keep_arrays)
        st->put(ch);
      array++;
      continue;
    case 'L':
      {
        if (prev_type)  st->put(',');
        int start = i+1, slash = start;
        while (++i < len && (ch = sig->byte_at(i)) != ';') {
          if (ch == '/' || ch == '.' || ch == '$')  slash = i+1;
        }
        if (slash < i)  start = slash;
        if (!keep_basic_names) {
          st->put('L');
        } else {
          for (int j = start; j < i; j++)
            st->put(sig->byte_at(j));
          prev_type = true;
        }
        break;
      }
    default:
      {
        if (array && char2type(ch) != T_ILLEGAL && !keep_arrays) {
          ch = '[';
          array = 0;
        }
        if (prev_type)  st->put(',');
        const char* n = NULL;
        if (keep_basic_names)
          n = type2name(char2type(ch));
        if (n == NULL) {
          // unknown letter, or we don't want to know its name
          st->put(ch);
        } else {
          st->print(n);
          prev_type = true;
        }
        break;
      }
    }
    // Switch break goes here to take care of array suffix:
    if (prev_type) {
      while (array > 0) {
        st->print("[]");
        --array;
      }
    }
    array = 0;
  }
}



static oop object_java_mirror() {
  return SystemDictionary::Object_klass()->java_mirror();
}

oop MethodHandles::field_name_or_null(Symbol* s) {
  if (s == NULL)  return NULL;
  return StringTable::lookup(s);
}

oop MethodHandles::field_signature_type_or_null(Symbol* s) {
  if (s == NULL)  return NULL;
  BasicType bt = FieldType::basic_type(s);
  if (is_java_primitive(bt)) {
    assert(s->utf8_length() == 1, "");
    return java_lang_Class::primitive_mirror(bt);
  }
  // Here are some more short cuts for common types.
  // They are optional, since reference types can be resolved lazily.
  if (bt == T_OBJECT) {
    if (s == vmSymbols::object_signature()) {
      return object_java_mirror();
    } else if (s == vmSymbols::class_signature()) {
      return SystemDictionary::Class_klass()->java_mirror();
    } else if (s == vmSymbols::string_signature()) {
      return SystemDictionary::String_klass()->java_mirror();
    }
  }
  return NULL;
}


// An unresolved member name is a mere symbolic reference.
// Resolving it plants a vmtarget/vmindex in it,
// which refers directly to JVM internals.
Handle MethodHandles::resolve_MemberName(Handle mname, KlassHandle caller, TRAPS) {
  Handle empty;
  assert(java_lang_invoke_MemberName::is_instance(mname()), "");

  if (java_lang_invoke_MemberName::vmtarget(mname()) != NULL) {
    // Already resolved.
    DEBUG_ONLY(int vmindex = java_lang_invoke_MemberName::vmindex(mname()));
    assert(vmindex >= Method::nonvirtual_vtable_index, "");
    return mname;
  }

  Handle defc_oop(THREAD, java_lang_invoke_MemberName::clazz(mname()));
  Handle name_str(THREAD, java_lang_invoke_MemberName::name( mname()));
  Handle type_str(THREAD, java_lang_invoke_MemberName::type( mname()));
  int    flags    =       java_lang_invoke_MemberName::flags(mname());
  int    ref_kind =       (flags >> REFERENCE_KIND_SHIFT) & REFERENCE_KIND_MASK;
  if (!ref_kind_is_valid(ref_kind)) {
    THROW_MSG_(vmSymbols::java_lang_InternalError(), "obsolete MemberName format", empty);
  }

  DEBUG_ONLY(int old_vmindex);
  assert((old_vmindex = java_lang_invoke_MemberName::vmindex(mname())) == 0, "clean input");

  if (defc_oop.is_null() || name_str.is_null() || type_str.is_null()) {
    THROW_MSG_(vmSymbols::java_lang_IllegalArgumentException(), "nothing to resolve", empty);
  }

  instanceKlassHandle defc;
  {
    Klass* defc_klass = java_lang_Class::as_Klass(defc_oop());
    if (defc_klass == NULL)  return empty;  // a primitive; no resolution possible
    if (!defc_klass->oop_is_instance()) {
      if (!defc_klass->oop_is_array())  return empty;
      defc_klass = SystemDictionary::Object_klass();
    }
    defc = instanceKlassHandle(THREAD, defc_klass);
  }
  if (defc.is_null()) {
    THROW_MSG_(vmSymbols::java_lang_InternalError(), "primitive class", empty);
  }
  defc->link_class(CHECK_(empty));  // possible safepoint

  // convert the external string name to an internal symbol
  TempNewSymbol name = java_lang_String::as_symbol_or_null(name_str());
  if (name == NULL)  return empty;  // no such name
  if (name == vmSymbols::class_initializer_name())
    return empty; // illegal name

  vmIntrinsics::ID mh_invoke_id = vmIntrinsics::_none;
  if ((flags & ALL_KINDS) == IS_METHOD &&
      (defc() == SystemDictionary::MethodHandle_klass()) &&
      (ref_kind == JVM_REF_invokeVirtual ||
       ref_kind == JVM_REF_invokeSpecial ||
       // static invocation mode is required for _linkToVirtual, etc.:
       ref_kind == JVM_REF_invokeStatic)) {
    vmIntrinsics::ID iid = signature_polymorphic_name_id(name);
    if (iid != vmIntrinsics::_none &&
        ((ref_kind == JVM_REF_invokeStatic) == is_signature_polymorphic_static(iid))) {
      // Virtual methods invoke and invokeExact, plus internal invokers like _invokeBasic.
      // For a static reference it could an internal linkage routine like _linkToVirtual, etc.
      mh_invoke_id = iid;
    }
  }

  // convert the external string or reflective type to an internal signature
  TempNewSymbol type = lookup_signature(type_str(), (mh_invoke_id != vmIntrinsics::_none), CHECK_(empty));
  if (type == NULL)  return empty;  // no such signature exists in the VM

  // Time to do the lookup.
  switch (flags & ALL_KINDS) {
  case IS_METHOD:
    {
      CallInfo result;
      {
        assert(!HAS_PENDING_EXCEPTION, "");
        if (ref_kind == JVM_REF_invokeStatic) {
          LinkResolver::resolve_static_call(result,
                        defc, name, type, caller, caller.not_null(), false, THREAD);
        } else if (ref_kind == JVM_REF_invokeInterface) {
          LinkResolver::resolve_interface_call(result, Handle(), defc,
                        defc, name, type, caller, caller.not_null(), false, THREAD);
        } else if (mh_invoke_id != vmIntrinsics::_none) {
          assert(!is_signature_polymorphic_static(mh_invoke_id), "");
          LinkResolver::resolve_handle_call(result,
                        defc, name, type, caller, THREAD);
        } else if (ref_kind == JVM_REF_invokeSpecial) {
          LinkResolver::resolve_special_call(result,
                        defc, name, type, caller, caller.not_null(), THREAD);
        } else if (ref_kind == JVM_REF_invokeVirtual) {
          LinkResolver::resolve_virtual_call(result, Handle(), defc,
                        defc, name, type, caller, caller.not_null(), false, THREAD);
        } else {
          assert(false, err_msg("ref_kind=%d", ref_kind));
        }
        if (HAS_PENDING_EXCEPTION) {
          return empty;
        }
      }
      if (result.resolved_appendix().not_null()) {
        // The resolved MemberName must not be accompanied by an appendix argument,
        // since there is no way to bind this value into the MemberName.
        // Caller is responsible to prevent this from happening.
        THROW_MSG_(vmSymbols::java_lang_InternalError(), "appendix", empty);
      }
      oop mname2 = init_method_MemberName(mname, result);
      return Handle(THREAD, mname2);
    }
  case IS_CONSTRUCTOR:
    {
      CallInfo result;
      {
        assert(!HAS_PENDING_EXCEPTION, "");
        if (name == vmSymbols::object_initializer_name()) {
          LinkResolver::resolve_special_call(result,
                        defc, name, type, caller, caller.not_null(), THREAD);
        } else {
          break;                // will throw after end of switch
        }
        if (HAS_PENDING_EXCEPTION) {
          return empty;
        }
      }
      assert(result.is_statically_bound(), "");
      oop mname2 = init_method_MemberName(mname, result);
      return Handle(THREAD, mname2);
    }
  case IS_FIELD:
    {
      fieldDescriptor result; // find_field initializes fd if found
      {
        assert(!HAS_PENDING_EXCEPTION, "");
        LinkResolver::resolve_field(result, defc, name, type, caller, Bytecodes::_nop, false, false, THREAD);
        if (HAS_PENDING_EXCEPTION) {
          return empty;
        }
      }
      oop mname2 = init_field_MemberName(mname, result, ref_kind_is_setter(ref_kind));
      return Handle(THREAD, mname2);
    }
  default:
    THROW_MSG_(vmSymbols::java_lang_InternalError(), "unrecognized MemberName format", empty);
  }

  return empty;
}

// Conversely, a member name which is only initialized from JVM internals
// may have null defc, name, and type fields.
// Resolving it plants a vmtarget/vmindex in it,
// which refers directly to JVM internals.
void MethodHandles::expand_MemberName(Handle mname, int suppress, TRAPS) {
  assert(java_lang_invoke_MemberName::is_instance(mname()), "");
  Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
  int vmindex  = java_lang_invoke_MemberName::vmindex(mname());
  if (vmtarget == NULL) {
    THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), "nothing to expand");
  }

  bool have_defc = (java_lang_invoke_MemberName::clazz(mname()) != NULL);
  bool have_name = (java_lang_invoke_MemberName::name(mname()) != NULL);
  bool have_type = (java_lang_invoke_MemberName::type(mname()) != NULL);
  int flags      = java_lang_invoke_MemberName::flags(mname());

  if (suppress != 0) {
    if (suppress & _suppress_defc)  have_defc = true;
    if (suppress & _suppress_name)  have_name = true;
    if (suppress & _suppress_type)  have_type = true;
  }

  if (have_defc && have_name && have_type)  return;  // nothing needed

  switch (flags & ALL_KINDS) {
  case IS_METHOD:
  case IS_CONSTRUCTOR:
    {
      assert(vmtarget->is_method(), "method or constructor vmtarget is Method*");
      methodHandle m(THREAD, (Method*)vmtarget);
      DEBUG_ONLY(vmtarget = NULL);  // safety
      if (m.is_null())  break;
      if (!have_defc) {
        InstanceKlass* defc = m->method_holder();
        java_lang_invoke_MemberName::set_clazz(mname(), defc->java_mirror());
      }
      if (!have_name) {
        //not java_lang_String::create_from_symbol; let's intern member names
        Handle name = StringTable::intern(m->name(), CHECK);
        java_lang_invoke_MemberName::set_name(mname(), name());
      }
      if (!have_type) {
        Handle type = java_lang_String::create_from_symbol(m->signature(), CHECK);
        java_lang_invoke_MemberName::set_type(mname(), type());
      }
      return;
    }
  case IS_FIELD:
    {
      assert(vmtarget->is_klass(), "field vmtarget is Klass*");
      if (!((Klass*) vmtarget)->oop_is_instance())  break;
      instanceKlassHandle defc(THREAD, (Klass*) vmtarget);
      DEBUG_ONLY(vmtarget = NULL);  // safety
      bool is_static = ((flags & JVM_ACC_STATIC) != 0);
      fieldDescriptor fd; // find_field initializes fd if found
      if (!defc->find_field_from_offset(vmindex, is_static, &fd))
        break;                  // cannot expand
      if (!have_defc) {
        java_lang_invoke_MemberName::set_clazz(mname(), defc->java_mirror());
      }
      if (!have_name) {
        //not java_lang_String::create_from_symbol; let's intern member names
        Handle name = StringTable::intern(fd.name(), CHECK);
        java_lang_invoke_MemberName::set_name(mname(), name());
      }
      if (!have_type) {
        // If it is a primitive field type, don't mess with short strings like "I".
        Handle type = field_signature_type_or_null(fd.signature());
        if (type.is_null()) {
          java_lang_String::create_from_symbol(fd.signature(), CHECK);
        }
        java_lang_invoke_MemberName::set_type(mname(), type());
      }
      return;
    }
  }
  THROW_MSG(vmSymbols::java_lang_InternalError(), "unrecognized MemberName format");
}

int MethodHandles::find_MemberNames(KlassHandle k,
                                    Symbol* name, Symbol* sig,
                                    int mflags, KlassHandle caller,
                                    int skip, objArrayHandle results) {
  // %%% take caller into account!

  Thread* thread = Thread::current();

  if (k.is_null() || !k->oop_is_instance())  return -1;

  int rfill = 0, rlimit = results->length(), rskip = skip;
  // overflow measurement:
  int overflow = 0, overflow_limit = MAX2(1000, rlimit);

  int match_flags = mflags;
  bool search_superc = ((match_flags & SEARCH_SUPERCLASSES) != 0);
  bool search_intfc  = ((match_flags & SEARCH_INTERFACES)   != 0);
  bool local_only = !(search_superc | search_intfc);
  bool classes_only = false;

  if (name != NULL) {
    if (name->utf8_length() == 0)  return 0; // a match is not possible
  }
  if (sig != NULL) {
    if (sig->utf8_length() == 0)  return 0; // a match is not possible
    if (sig->byte_at(0) == '(')
      match_flags &= ~(IS_FIELD | IS_TYPE);
    else
      match_flags &= ~(IS_CONSTRUCTOR | IS_METHOD);
  }

  if ((match_flags & IS_TYPE) != 0) {
    // NYI, and Core Reflection works quite well for this query
  }

  if ((match_flags & IS_FIELD) != 0) {
    for (FieldStream st(k(), local_only, !search_intfc); !st.eos(); st.next()) {
      if (name != NULL && st.name() != name)
          continue;
      if (sig != NULL && st.signature() != sig)
        continue;
      // passed the filters
      if (rskip > 0) {
        --rskip;
      } else if (rfill < rlimit) {
        Handle result(thread, results->obj_at(rfill++));
        if (!java_lang_invoke_MemberName::is_instance(result()))
          return -99;  // caller bug!
        oop saved = MethodHandles::init_field_MemberName(result, st.field_descriptor());
        if (saved != result())
          results->obj_at_put(rfill-1, saved);  // show saved instance to user
      } else if (++overflow >= overflow_limit) {
        match_flags = 0; break; // got tired of looking at overflow
      }
    }
  }

  if ((match_flags & (IS_METHOD | IS_CONSTRUCTOR)) != 0) {
    // watch out for these guys:
    Symbol* init_name   = vmSymbols::object_initializer_name();
    Symbol* clinit_name = vmSymbols::class_initializer_name();
    if (name == clinit_name)  clinit_name = NULL; // hack for exposing <clinit>
    bool negate_name_test = false;
    // fix name so that it captures the intention of IS_CONSTRUCTOR
    if (!(match_flags & IS_METHOD)) {
      // constructors only
      if (name == NULL) {
        name = init_name;
      } else if (name != init_name) {
        return 0;               // no constructors of this method name
      }
    } else if (!(match_flags & IS_CONSTRUCTOR)) {
      // methods only
      if (name == NULL) {
        name = init_name;
        negate_name_test = true; // if we see the name, we *omit* the entry
      } else if (name == init_name) {
        return 0;               // no methods of this constructor name
      }
    } else {
      // caller will accept either sort; no need to adjust name
    }
    for (MethodStream st(k(), local_only, !search_intfc); !st.eos(); st.next()) {
      Method* m = st.method();
      Symbol* m_name = m->name();
      if (m_name == clinit_name)
        continue;
      if (name != NULL && ((m_name != name) ^ negate_name_test))
          continue;
      if (sig != NULL && m->signature() != sig)
        continue;
      // passed the filters
      if (rskip > 0) {
        --rskip;
      } else if (rfill < rlimit) {
        Handle result(thread, results->obj_at(rfill++));
        if (!java_lang_invoke_MemberName::is_instance(result()))
          return -99;  // caller bug!
        CallInfo info(m);
        oop saved = MethodHandles::init_method_MemberName(result, info);
        if (saved != result())
          results->obj_at_put(rfill-1, saved);  // show saved instance to user
      } else if (++overflow >= overflow_limit) {
        match_flags = 0; break; // got tired of looking at overflow
      }
    }
  }

  // return number of elements we at leasted wanted to initialize
  return rfill + overflow;
}

//------------------------------------------------------------------------------
// MemberNameTable
//

MemberNameTable::MemberNameTable(int methods_cnt)
                  : GrowableArray<jweak>(methods_cnt, true) {
  assert_locked_or_safepoint(MemberNameTable_lock);
}

MemberNameTable::~MemberNameTable() {
  assert_locked_or_safepoint(MemberNameTable_lock);
  int len = this->length();

  for (int idx = 0; idx < len; idx++) {
    jweak ref = this->at(idx);
    JNIHandles::destroy_weak_global(ref);
  }
}

void MemberNameTable::add_member_name(int index, jweak mem_name_wref) {
  assert_locked_or_safepoint(MemberNameTable_lock);
  this->at_put_grow(index, mem_name_wref);
}

// Return a member name oop or NULL.
oop MemberNameTable::get_member_name(int index) {
  assert_locked_or_safepoint(MemberNameTable_lock);

  jweak ref = this->at(index);
  oop mem_name = JNIHandles::resolve(ref);
  return mem_name;
}

#if INCLUDE_JVMTI
oop MemberNameTable::find_member_name_by_method(Method* old_method) {
  assert_locked_or_safepoint(MemberNameTable_lock);
  oop found = NULL;
  int len = this->length();

  for (int idx = 0; idx < len; idx++) {
    oop mem_name = JNIHandles::resolve(this->at(idx));
    if (mem_name == NULL) {
      continue;
    }
    Method* method = (Method*)java_lang_invoke_MemberName::vmtarget(mem_name);
    if (method == old_method) {
      found = mem_name;
      break;
    }
  }
  return found;
}

// It is called at safepoint only
void MemberNameTable::adjust_method_entries(Method** old_methods, Method** new_methods,
                                            int methods_length, bool *trace_name_printed) {
  assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
  // search the MemberNameTable for uses of either obsolete or EMCP methods
  for (int j = 0; j < methods_length; j++) {
    Method* old_method = old_methods[j];
    Method* new_method = new_methods[j];
    oop mem_name = find_member_name_by_method(old_method);
    if (mem_name != NULL) {
      java_lang_invoke_MemberName::adjust_vmtarget(mem_name, new_method);

      if (RC_TRACE_IN_RANGE(0x00100000, 0x00400000)) {
        if (!(*trace_name_printed)) {
          // RC_TRACE_MESG macro has an embedded ResourceMark
          RC_TRACE_MESG(("adjust: name=%s",
                         old_method->method_holder()->external_name()));
          *trace_name_printed = true;
        }
        // RC_TRACE macro has an embedded ResourceMark
        RC_TRACE(0x00400000, ("MemberName method update: %s(%s)",
                              new_method->name()->as_C_string(),
                              new_method->signature()->as_C_string()));
      }
    }
  }
}
#endif // INCLUDE_JVMTI

//
// Here are the native methods in java.lang.invoke.MethodHandleNatives
// They are the private interface between this JVM and the HotSpot-specific
// Java code that implements JSR 292 method handles.
//
// Note:  We use a JVM_ENTRY macro to define each of these, for this is the way
// that intrinsic (non-JNI) native methods are defined in HotSpot.
//

JVM_ENTRY(jint, MHN_getConstant(JNIEnv *env, jobject igcls, jint which)) {
  switch (which) {
  case MethodHandles::GC_COUNT_GWT:
#ifdef COMPILER2
    return true;
#else
    return false;
#endif
  }
  return 0;
}
JVM_END

#ifndef PRODUCT
#define EACH_NAMED_CON(template, requirement) \
    template(MethodHandles,GC_COUNT_GWT) \
    template(java_lang_invoke_MemberName,MN_IS_METHOD) \
    template(java_lang_invoke_MemberName,MN_IS_CONSTRUCTOR) \
    template(java_lang_invoke_MemberName,MN_IS_FIELD) \
    template(java_lang_invoke_MemberName,MN_IS_TYPE) \
    template(java_lang_invoke_MemberName,MN_CALLER_SENSITIVE) \
    template(java_lang_invoke_MemberName,MN_SEARCH_SUPERCLASSES) \
    template(java_lang_invoke_MemberName,MN_SEARCH_INTERFACES) \
    template(java_lang_invoke_MemberName,MN_REFERENCE_KIND_SHIFT) \
    template(java_lang_invoke_MemberName,MN_REFERENCE_KIND_MASK) \
    template(MethodHandles,GC_LAMBDA_SUPPORT) \
    /*end*/

#define IGNORE_REQ(req_expr) /* req_expr */
#define ONE_PLUS(scope,value) 1+
static const int con_value_count = EACH_NAMED_CON(ONE_PLUS, IGNORE_REQ) 0;
#define VALUE_COMMA(scope,value) scope::value,
static const int con_values[con_value_count+1] = { EACH_NAMED_CON(VALUE_COMMA, IGNORE_REQ) 0 };
#define STRING_NULL(scope,value) #value "\0"
static const char con_names[] = { EACH_NAMED_CON(STRING_NULL, IGNORE_REQ) };

static bool advertise_con_value(int which) {
  if (which < 0)  return false;
  bool ok = true;
  int count = 0;
#define INC_COUNT(scope,value) \
  ++count;
#define CHECK_REQ(req_expr) \
  if (which < count)  return ok; \
  ok = (req_expr);
  EACH_NAMED_CON(INC_COUNT, CHECK_REQ);
#undef INC_COUNT
#undef CHECK_REQ
  assert(count == con_value_count, "");
  if (which < count)  return ok;
  return false;
}

#undef ONE_PLUS
#undef VALUE_COMMA
#undef STRING_NULL
#undef EACH_NAMED_CON
#endif // PRODUCT

JVM_ENTRY(jint, MHN_getNamedCon(JNIEnv *env, jobject igcls, jint which, jobjectArray box_jh)) {
#ifndef PRODUCT
  if (advertise_con_value(which)) {
    assert(which >= 0 && which < con_value_count, "");
    int con = con_values[which];
    objArrayHandle box(THREAD, (objArrayOop) JNIHandles::resolve(box_jh));
    if (box.not_null() && box->klass() == Universe::objectArrayKlassObj() && box->length() > 0) {
      const char* str = &con_names[0];
      for (int i = 0; i < which; i++)
        str += strlen(str) + 1;   // skip name and null
      oop name = java_lang_String::create_oop_from_str(str, CHECK_0);  // possible safepoint
      box->obj_at_put(0, name);
    }
    return con;
  }
#endif
  return 0;
}
JVM_END

// void init(MemberName self, AccessibleObject ref)
JVM_ENTRY(void, MHN_init_Mem(JNIEnv *env, jobject igcls, jobject mname_jh, jobject target_jh)) {
  if (mname_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "mname is null"); }
  if (target_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "target is null"); }
  Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));
  Handle target(THREAD, JNIHandles::resolve_non_null(target_jh));
  MethodHandles::init_MemberName(mname, target);
}
JVM_END

// void expand(MemberName self)
JVM_ENTRY(void, MHN_expand_Mem(JNIEnv *env, jobject igcls, jobject mname_jh)) {
  if (mname_jh == NULL) { THROW_MSG(vmSymbols::java_lang_InternalError(), "mname is null"); }
  Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));
  MethodHandles::expand_MemberName(mname, 0, CHECK);
}
JVM_END

// void resolve(MemberName self, Class<?> caller)
JVM_ENTRY(jobject, MHN_resolve_Mem(JNIEnv *env, jobject igcls, jobject mname_jh, jclass caller_jh)) {
  if (mname_jh == NULL) { THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "mname is null"); }
  Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));

  // The trusted Java code that calls this method should already have performed
  // access checks on behalf of the given caller.  But, we can verify this.
  if (VerifyMethodHandles && caller_jh != NULL &&
      java_lang_invoke_MemberName::clazz(mname()) != NULL) {
    Klass* reference_klass = java_lang_Class::as_Klass(java_lang_invoke_MemberName::clazz(mname()));
    if (reference_klass != NULL && reference_klass->oop_is_objArray()) {
      reference_klass = ObjArrayKlass::cast(reference_klass)->bottom_klass();
    }

    // Reflection::verify_class_access can only handle instance classes.
    if (reference_klass != NULL && reference_klass->oop_is_instance()) {
      // Emulate LinkResolver::check_klass_accessability.
      Klass* caller = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(caller_jh));
      if (!Reflection::verify_class_access(caller,
                                           reference_klass,
                                           true)) {
        THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), reference_klass->external_name());
      }
    }
  }

  KlassHandle caller(THREAD,
                     caller_jh == NULL ? (Klass*) NULL :
                     java_lang_Class::as_Klass(JNIHandles::resolve_non_null(caller_jh)));
  Handle resolved = MethodHandles::resolve_MemberName(mname, caller, CHECK_NULL);

  if (resolved.is_null()) {
    int flags = java_lang_invoke_MemberName::flags(mname());
    int ref_kind = (flags >> REFERENCE_KIND_SHIFT) & REFERENCE_KIND_MASK;
    if (!MethodHandles::ref_kind_is_valid(ref_kind)) {
      THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "obsolete MemberName format");
    }
    if ((flags & ALL_KINDS) == IS_FIELD) {
      THROW_MSG_NULL(vmSymbols::java_lang_NoSuchMethodError(), "field resolution failed");
    } else if ((flags & ALL_KINDS) == IS_METHOD ||
               (flags & ALL_KINDS) == IS_CONSTRUCTOR) {
      THROW_MSG_NULL(vmSymbols::java_lang_NoSuchFieldError(), "method resolution failed");
    } else {
      THROW_MSG_NULL(vmSymbols::java_lang_LinkageError(), "resolution failed");
    }
  }

  return JNIHandles::make_local(THREAD, resolved());
}
JVM_END

static jlong find_member_field_offset(oop mname, bool must_be_static, TRAPS) {
  if (mname == NULL ||
      java_lang_invoke_MemberName::vmtarget(mname) == NULL) {
    THROW_MSG_0(vmSymbols::java_lang_InternalError(), "mname not resolved");
  } else {
    int flags = java_lang_invoke_MemberName::flags(mname);
    if ((flags & IS_FIELD) != 0 &&
        (must_be_static
         ? (flags & JVM_ACC_STATIC) != 0
         : (flags & JVM_ACC_STATIC) == 0)) {
      int vmindex = java_lang_invoke_MemberName::vmindex(mname);
      return (jlong) vmindex;
    }
  }
  const char* msg = (must_be_static ? "static field required" : "non-static field required");
  THROW_MSG_0(vmSymbols::java_lang_InternalError(), msg);
  return 0;
}

JVM_ENTRY(jlong, MHN_objectFieldOffset(JNIEnv *env, jobject igcls, jobject mname_jh)) {
  return find_member_field_offset(JNIHandles::resolve(mname_jh), false, THREAD);
}
JVM_END

JVM_ENTRY(jlong, MHN_staticFieldOffset(JNIEnv *env, jobject igcls, jobject mname_jh)) {
  return find_member_field_offset(JNIHandles::resolve(mname_jh), true, THREAD);
}
JVM_END

JVM_ENTRY(jobject, MHN_staticFieldBase(JNIEnv *env, jobject igcls, jobject mname_jh)) {
  // use the other function to perform sanity checks:
  jlong ignore = find_member_field_offset(JNIHandles::resolve(mname_jh), true, CHECK_NULL);
  oop clazz = java_lang_invoke_MemberName::clazz(JNIHandles::resolve_non_null(mname_jh));
  return JNIHandles::make_local(THREAD, clazz);
}
JVM_END

JVM_ENTRY(jobject, MHN_getMemberVMInfo(JNIEnv *env, jobject igcls, jobject mname_jh)) {
  if (mname_jh == NULL)  return NULL;
  Handle mname(THREAD, JNIHandles::resolve_non_null(mname_jh));
  intptr_t vmindex  = java_lang_invoke_MemberName::vmindex(mname());
  Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
  objArrayHandle result = oopFactory::new_objArray(SystemDictionary::Object_klass(), 2, CHECK_NULL);
  jvalue vmindex_value; vmindex_value.j = (long)vmindex;
  oop x = java_lang_boxing_object::create(T_LONG, &vmindex_value, CHECK_NULL);
  result->obj_at_put(0, x);
  x = NULL;
  if (vmtarget == NULL) {
    x = NULL;
  } else if (vmtarget->is_klass()) {
    x = ((Klass*) vmtarget)->java_mirror();
  } else if (vmtarget->is_method()) {
    x = mname();
  }
  result->obj_at_put(1, x);
  return JNIHandles::make_local(env, result());
}
JVM_END



//  static native int getMembers(Class<?> defc, String matchName, String matchSig,
//          int matchFlags, Class<?> caller, int skip, MemberName[] results);
JVM_ENTRY(jint, MHN_getMembers(JNIEnv *env, jobject igcls,
                               jclass clazz_jh, jstring name_jh, jstring sig_jh,
                               int mflags, jclass caller_jh, jint skip, jobjectArray results_jh)) {
  if (clazz_jh == NULL || results_jh == NULL)  return -1;
  KlassHandle k(THREAD, java_lang_Class::as_Klass(JNIHandles::resolve_non_null(clazz_jh)));

  objArrayHandle results(THREAD, (objArrayOop) JNIHandles::resolve(results_jh));
  if (results.is_null() || !results->is_objArray())  return -1;

  TempNewSymbol name = NULL;
  TempNewSymbol sig = NULL;
  if (name_jh != NULL) {
    name = java_lang_String::as_symbol_or_null(JNIHandles::resolve_non_null(name_jh));
    if (name == NULL)  return 0; // a match is not possible
  }
  if (sig_jh != NULL) {
    sig = java_lang_String::as_symbol_or_null(JNIHandles::resolve_non_null(sig_jh));
    if (sig == NULL)  return 0; // a match is not possible
  }

  KlassHandle caller;
  if (caller_jh != NULL) {
    oop caller_oop = JNIHandles::resolve_non_null(caller_jh);
    if (!java_lang_Class::is_instance(caller_oop))  return -1;
    caller = KlassHandle(THREAD, java_lang_Class::as_Klass(caller_oop));
  }

  if (name != NULL && sig != NULL && results.not_null()) {
    // try a direct resolve
    // %%% TO DO
  }

  int res = MethodHandles::find_MemberNames(k, name, sig, mflags,
                                            caller, skip, results);
  // TO DO: expand at least some of the MemberNames, to avoid massive callbacks
  return res;
}
JVM_END

JVM_ENTRY(void, MHN_setCallSiteTargetNormal(JNIEnv* env, jobject igcls, jobject call_site_jh, jobject target_jh)) {
  Handle call_site(THREAD, JNIHandles::resolve_non_null(call_site_jh));
  Handle target   (THREAD, JNIHandles::resolve(target_jh));
  {
    // Walk all nmethods depending on this call site.
    MutexLocker mu(Compile_lock, thread);
    Universe::flush_dependents_on(call_site, target);
    java_lang_invoke_CallSite::set_target(call_site(), target());
  }
}
JVM_END

JVM_ENTRY(void, MHN_setCallSiteTargetVolatile(JNIEnv* env, jobject igcls, jobject call_site_jh, jobject target_jh)) {
  Handle call_site(THREAD, JNIHandles::resolve_non_null(call_site_jh));
  Handle target   (THREAD, JNIHandles::resolve(target_jh));
  {
    // Walk all nmethods depending on this call site.
    MutexLocker mu(Compile_lock, thread);
    Universe::flush_dependents_on(call_site, target);
    java_lang_invoke_CallSite::set_target_volatile(call_site(), target());
  }
}
JVM_END

/**
 * Throws a java/lang/UnsupportedOperationException unconditionally.
 * This is required by the specification of MethodHandle.invoke if
 * invoked directly.
 */
JVM_ENTRY(jobject, MH_invoke_UOE(JNIEnv* env, jobject mh, jobjectArray args)) {
  THROW_MSG_NULL(vmSymbols::java_lang_UnsupportedOperationException(), "MethodHandle.invoke cannot be invoked reflectively");
  return NULL;
}
JVM_END

/**
 * Throws a java/lang/UnsupportedOperationException unconditionally.
 * This is required by the specification of MethodHandle.invokeExact if
 * invoked directly.
 */
JVM_ENTRY(jobject, MH_invokeExact_UOE(JNIEnv* env, jobject mh, jobjectArray args)) {
  THROW_MSG_NULL(vmSymbols::java_lang_UnsupportedOperationException(), "MethodHandle.invokeExact cannot be invoked reflectively");
  return NULL;
}
JVM_END

/// JVM_RegisterMethodHandleMethods

#undef CS  // Solaris builds complain

#define LANG "Ljava/lang/"
#define JLINV "Ljava/lang/invoke/"

#define OBJ   LANG"Object;"
#define CLS   LANG"Class;"
#define STRG  LANG"String;"
#define CS    JLINV"CallSite;"
#define MT    JLINV"MethodType;"
#define MH    JLINV"MethodHandle;"
#define MEM   JLINV"MemberName;"

#define CC (char*)  /*cast a literal from (const char*)*/
#define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)

// These are the native methods on java.lang.invoke.MethodHandleNatives.
static JNINativeMethod MHN_methods[] = {
  {CC"init",                      CC"("MEM""OBJ")V",                     FN_PTR(MHN_init_Mem)},
  {CC"expand",                    CC"("MEM")V",                          FN_PTR(MHN_expand_Mem)},
  {CC"resolve",                   CC"("MEM""CLS")"MEM,                   FN_PTR(MHN_resolve_Mem)},
  {CC"getConstant",               CC"(I)I",                              FN_PTR(MHN_getConstant)},
  //  static native int getNamedCon(int which, Object[] name)
  {CC"getNamedCon",               CC"(I["OBJ")I",                        FN_PTR(MHN_getNamedCon)},
  //  static native int getMembers(Class<?> defc, String matchName, String matchSig,
  //          int matchFlags, Class<?> caller, int skip, MemberName[] results);
  {CC"getMembers",                CC"("CLS""STRG""STRG"I"CLS"I["MEM")I", FN_PTR(MHN_getMembers)},
  {CC"objectFieldOffset",         CC"("MEM")J",                          FN_PTR(MHN_objectFieldOffset)},
  {CC"setCallSiteTargetNormal",   CC"("CS""MH")V",                       FN_PTR(MHN_setCallSiteTargetNormal)},
  {CC"setCallSiteTargetVolatile", CC"("CS""MH")V",                       FN_PTR(MHN_setCallSiteTargetVolatile)},
  {CC"staticFieldOffset",         CC"("MEM")J",                          FN_PTR(MHN_staticFieldOffset)},
  {CC"staticFieldBase",           CC"("MEM")"OBJ,                        FN_PTR(MHN_staticFieldBase)},
  {CC"getMemberVMInfo",           CC"("MEM")"OBJ,                        FN_PTR(MHN_getMemberVMInfo)}
};

static JNINativeMethod MH_methods[] = {
  // UnsupportedOperationException throwers
  {CC"invoke",                    CC"(["OBJ")"OBJ,                       FN_PTR(MH_invoke_UOE)},
  {CC"invokeExact",               CC"(["OBJ")"OBJ,                       FN_PTR(MH_invokeExact_UOE)}
};

/**
 * Helper method to register native methods.
 */
static bool register_natives(JNIEnv* env, jclass clazz, const JNINativeMethod* methods, jint nMethods) {
  int status = env->RegisterNatives(clazz, methods, nMethods);
  if (status != JNI_OK || env->ExceptionOccurred()) {
    warning("JSR 292 method handle code is mismatched to this JVM.  Disabling support.");
    env->ExceptionClear();
    return false;
  }
  return true;
}

/**
 * This one function is exported, used by NativeLookup.
 */
JVM_ENTRY(void, JVM_RegisterMethodHandleMethods(JNIEnv *env, jclass MHN_class)) {
  if (!EnableInvokeDynamic) {
    warning("JSR 292 is disabled in this JVM.  Use -XX:+UnlockDiagnosticVMOptions -XX:+EnableInvokeDynamic to enable.");
    return;  // bind nothing
  }

  assert(!MethodHandles::enabled(), "must not be enabled");
  bool enable_MH = true;

  jclass MH_class = NULL;
  if (SystemDictionary::MethodHandle_klass() == NULL) {
    enable_MH = false;
  } else {
    oop mirror = SystemDictionary::MethodHandle_klass()->java_mirror();
    MH_class = (jclass) JNIHandles::make_local(env, mirror);
  }

  if (enable_MH) {
    ThreadToNativeFromVM ttnfv(thread);

    if (enable_MH) {
      enable_MH = register_natives(env, MHN_class, MHN_methods, sizeof(MHN_methods)/sizeof(JNINativeMethod));
    }
    if (enable_MH) {
      enable_MH = register_natives(env, MH_class, MH_methods, sizeof(MH_methods)/sizeof(JNINativeMethod));
    }
  }

  if (TraceInvokeDynamic) {
    tty->print_cr("MethodHandle support loaded (using LambdaForms)");
  }

  if (enable_MH) {
    MethodHandles::generate_adapters();
    MethodHandles::set_enabled(true);
  }
}
JVM_END

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